Same problem here using Squeeze. I just installed a few days ago. Also a Samsung Q45 laptop. $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03) $ ls -lah /sys/class/backlight/ total 0 drwxr-xr-x 2 root root 0 Aug 15 16:59 . drwxr-xr-x 42 root root 0 Aug 14 23:04 ..